Method of producing a fibrous article

ABSTRACT

The invention concerns a method of producing a fibrous article comprising employing at least one former at least one of whose surfaces is provided with substantially parallel recesses, laying a plurality of transverse lengths of fibrous material over the former so that the said transverse lengths extend transversely of the recesses and are spaced from each other longitudinally of the recesses, laying a longitudinal length of fibrous material in each said recess so that the said longitudinal lengths extend over the said transverse lengths and force respective portions of the latter into the recesses, forming at least one fibrous assembly having the shape of the respective said surface by bonding the transverse and longitudinal lengths together while the latter are on the former, and effecting relative separation between the said assembly and the former.

United States Patent [72] lnventors Jack Palfreyman;

Henry Edward Middleton, both of Derby, England 21] App1.No. 23,174 [22] Filed Mar. 27, 1970 [45] Patented Oct. 26, 1971 [73] Assignee Rolls Royce Limited Derby, England [32] Priority Apr. 2, 1969 [33] Great Britain [31] 17,238/69 [54] METHOD OF PRODUCING A FIBROUS ARTICLE 11 Claims, 6 Drawing Figs. 52] US. Cl 156/93, 28/7215,156/161,156/169,156/173,156/175, 156/181, 156/212 [51] Int. Cl ..B65h 81/02,

B65h 57/04, D04h 3/08 [50] FieldofSearch 156/161, 162,174,175,169,180,18l,l83,210,212,93; 28/1 SM, 1.2, 1.8, 72.15, 73 [56] References Cited UNITED STATES PATENTS 2,047,584 7/1936 Aarrap 156/210 Primary ExaminerCarl D. Quarfoith Assistant ExaminerR0ger S. Gaither AnorneyCushman, Darby and Cushman ABSTRACT: The invention concerns a method of producing a fibrous article comprising employing at least one former at least one of whose surfaces is provided with substantially parallel recesses, laying a plurality of transverse lengths of fibrous material over the former so that the said transverse lengths extend transversely of the recesses and are spaced from each other longitudinally of the recesses, laying a longitudinal length of fibrous material in each said recess so that the said longitudinal lengths extend over the said transverse lengths and force respective portions of the latter into the recesses, forming at least one fibrous assembly having the shape of the respective said surface by bonding the transverse and longitudinal lengths together while the latter are on the former, and effecting relative separation between the said assembly and the former.

PATENTEDucr 28 I971 SHEET 2 [IF 2 METHOD OF PRODUCING A FIBROUS ARTICLE This invention concerns a method of producing a fibrous article and although the invention is not so restricted it is more particularly concerned with a method of producing an aerofoil-shaped blade for use in a fluid flow machine such for example as a gas turbine engine.

The term blade is used in this specification in a broad sense as including bladelike members such as stator vanes.

According to the present invention, there is provided a method of producing a fibrous article comprising employing at least one former at least one of whose surfaces is provided with substantially parallel recesses, laying a plurality of transverse lengths of fibrous material over the or each former so that the said transverse lengths extend transversely of the recesses and are spaced from each other longitudinally of the recesses, laying a longitudinal length of fibrous material in each said recess so that the said longitudinal lengths extend over the said transverse lengths and force respectiveportions of the latter into the recesses, forming at least one fibrous assembly having the shape of the respective said surface by bonding the transverse and longitudinal lengths together while the latter are on the former, and effecting relative separation between the or each said assembly and the former.

The transverse lengths are preferably constituted by portions of at least one common transverse length of fibrous material. Thus there may be at least one pair of the said formers which are arranged in back-to-back relationship, the or each said common transverse length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.

The longitudinal lengths are preferably constituted by portions of at least one common longitudinal length of fibrous material. Thus there may be at least one pair of the said formers which are aligned with each other and are spaced from each other longitudinally of the recesses, the or each said common longitudinal length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.

After the said relative separation, the assemblies are preferably separated from each other.

After the said relative separation, further fibrous material may be wound transversely about the or each said assembly.

Moreover, after the said relative separation, at least one layer of material may be arranged at one end of the or each said assembly and may be interconnected therewith by employing additional fibrous material which extends longitudinally of the assembly. The additional fibrous material may be stitched through the said assembly.

The fibrous material may be fiber-reinforced mouldable material, the article being finally moulded.

The method may be employed to produce an aerofoilshaped blade for use in a fluid flow machine.

The invention also comprises a fibrous article when produced by the method set forth above.

The invention is illustrated, merely by way of example, in the accompanying diagrammatic drawings, in which:

FIGS. 1, 2, 4 and 5 illustrate diagrammatically various stages in a method of producing a fibrous article according to the present invention,

FIG. 3, which is a sectional view taken on the line A-A of FIG. 2, illustrates the shape of the assembly produced after the stage of the method illustrated inFlG. 2 has been completed, and

FIG. 6 is a diagrammatic sectional view of the blade after the stage of the method illustrated in FIG. 5 has been completed.

The drawings illustrate diagrammatically the production of a fiber-reinforced compressor rotor blade of a gas turbine engine. The fiber employed may, for example, be a carbon fiber produced from polyacrylonitrile, while this fiber may be used to reinforce a blade made of a mouldable synthetic resin material such, for example, as an epoxy resin. Many other materials are, however, usable in the production of the blade. For example, the fibrous material may be metallic, e.g. of

boron, while the fibrous material, whether formed or carbon or of a metal, may be coated with a metal (e.g. nickel) or with carbonaceous material. For convenience of description, however, the method will be described below on the basis that the blade is fonned from carbonaceous fibrous material produced from polyaerylonitrile, this fibrous material being coated with an uncured or partly cured epoxy resin.

1n the first stage of the method, which is illustrated in FIG. 1, a metal former I0 is employed having a surface 11 which is corrugated by reason of being provided with a plurality of substantially parallel longitudinally extending recesses 12. The former 10 is treated with a release agent and a plurality of transverse lengths 13 of fibrous material are then laid over the former 10 so that the transverse lengths 13 extend transversely of the recesses 12 and are spaced from each other longitudinally of these recesses.

Although the transverse lengths 13 are shown in FIG. 1 as being completely separate from each other, in practice it is more convenient to arrange that they are constituted by portions of at least one common transverse length of fibrous material. This may be easily effected by arranging that there is at least one pair of the formers 10 which are disposed in backto-back relationship, the or each said common transverse length being wound around the respective pair of fonners so that the said portions ultimately form part of two assemblies of fibrous material.

In the second stage of the method which is illustrated in FIG. 2, a longitudinal length 14 of fibrous material is laid in each recess 12 and is tensioned so that the said longitudinal lengths 14 extend over the said transverse lengths l3 and force respective portions of the latter into the recesses 12. When this has been done, a size is applied to the assembly of lengths 13, 14 so as to bond these lengths together and to give this assembly the shape of the surface 11.

After the application of this size, which occurs of course during the time that the transverse and longitudinal lengths l3, 14 are still on the former 10, relative separation is effected between the assembly so produced and the former 10. The resulting assembly is indicated at 15 in FIG. 3.

Although the longitudinal lengths 14 have been described above as though they were completely separate from each other, it is more convenient to arrange that they are constituted by portions of at least one common longitudinal length of fibrous material. This may for example be effected by providing at least one pair of the formers 10 which are longitudinally aligned with each other and are spaced from each other longitudinally with respect to the direction of the recesses 12, the or each said common longitudinal length being wound around the respective pair of formers 10 so that the said portions form parts of the two assemblies 15 which are ultimately produced.

Where such pairsof formers are employed, they are subsequently removed and the fibrous assemblies formed on the various surfaces 11 are separated from each other.

Prior to removing the former or formers the far ends of the longitudinal lengths 14 may, if desired, be clamped.

After the fon'ner or fon'ners have been removed, further fibrous material indicated at 16 is wound transversely about each assembly 15. This may be effected by winding loops of the material 16 about the assembly 15.

As will be appreciated, the longitudinal lengths 14 will, when the finished blade is mounted in a gas turbine engine, extend radially of the latter while the transverse lengths 13 will extend approximately axially thereof.

Such a finished blade, however, requires a root portion 20 (FIG. 6) of increased thickness, and this root portion is therefore built up from a number oflayers 21 ofa material such. for

example, as glass-reinforced plastics. Each said layer 2l'is arthe assembly in one direction, is stitched therethrough, and is then withdrawn (by separate means not shown) over the assembly in the opposite direction.

After each layer 21 has been so positioned, the layer of the additional fibrous material 22 may be appropriately cut to shape (by means not shown) so that the final blade has the desired form.

Two such blades may be formed simultaneously and then separated along the line 23.

Finally, the article which is illustrated in H6. 6 is shaped by moulding it to form.

Although the fibers have been described above as though they were individual fibers in practice they may be constituted by tows of fibers We claim:

1. A method of producing a fibrous article comprising employing at least one former at least one of whose surfaces is provided with substantially parallel recesses, laying a plurality of transverse lengths of fibrous material over the former so that the said transverse lengths extend transversely of the recesses and are spaced from each other longitudinally of the recesses, laying a longitudinal length of fibrous material in each said recess so that the said longitudinal lengths extend over the said transverse lengths and force respective portions of the latter into the recesses, forming at least one fibrous assembly having the shape of the respective said surface by bonding the transverse and longitudinal lengths together while the latter are on the former, and effecting relative separation between the said assembly and the former.

2. A method as claimed in claim 1 in which the transverse lengths are constituted by portions of at least one common transverse length of fibrous material.

3. A method as claimed in claim 2 in which there is at least one pair of the said formers which are arranged in back-toback relationship, the said common transverse length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.

4. A method as claimed in claim 3 in which, after the said relative separation, the assemblies are separated from each other.

5. A method as claimed in claim 1 in which the longitudinal lengths are constituted by portions of at least one common longitudinal length of fibrous material.

6. A method as claimed in claim 5 in which there is at least one pair of the said formers which are aligned with each other and are spaced from each other longitudinally of the recesses, the said common longitudinal length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.

7. A method as claimed in claim 1 in which, after the said relative separation, further fibrous material is wound transversely about the or each said assembly.

8. A method as claimed in claim I in which, alter the said relative separation, at least one layer of material is arranged at one end of the or each said assembly and is interconnected therewith by employing additional fibrous material which extends longitudinally of the assembly.

9. A method as claimed in claim 8 in which the additional fibrous material is stitched through the said assembly.

10. A method as claimed in claim 1 in which the fibrous material is fiber-reinforced mouldable material, the article being finally moulded.

11. A method as claimed in claim 1 in which the method is employed to produce an aerofoil-shaped blade for use in a fluid flow machine.

t 1! b i t 

2. A method as claimed in claim 1 in which the transverse lengths are constituted by portions of at least one common transverse length of fibrous material.
 3. A method as claimed in claim 2 in which there is at least one pair of the said formers which are arranged in back-to-back relationship, the said common transverse length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.
 4. A method as claimed in claim 3 in which, after the said relative separation, the assemblies are separated from each other.
 5. A method as claimed in claim 1 in which the longitudinal lengths are constituted by portions of at least one common longitudinal length of fibrous material.
 6. A method as claimed in claim 5 in which there is at least one pair of the said formers which are aligned with each other and are spaced from each other longitudinally of the recesses, the said common longitudinal length being wound around the respective pair of formers so that the said portions form parts of two said assemblies.
 7. A method as claimed in claim 1 in which, after the said relative separation, further fibrous material is wound transversely about the or each said assembly.
 8. A method as claimed in claim 1 in which, after the said relative separation, at least one layer of material is arranged at one end of the or each said assembly and is interconnected therewith by employing additional fibrous material which extends longitudinally of the assembly.
 9. A method as claimed in claim 8 in which the additional fibrous material is stitched through the said assembly.
 10. A method as claimed in claim 1 in which the fibrous material is fiber-reinforced mouldable material, the article being finally moulded.
 11. A method as claimed in claim 1 in which the method is employed to produce an aerofoil-shaped blade for use in a fluid flow machine. 